The present invention generally relates to medical implants and more specifically relates to inflatable prostheses, such as tissue expanders, suitable for implantation in a mammal.
Prostheses or implants for reconstruction and/or augmentation of the human body are well known.
Fluid filled prostheses, for example, mammary prostheses or breast implants, are widely used to replace excised tissue, for example after a radical mastectomy, or to augment the body to improve surface configurations. Although there are many applications where these are used, the most common is the mammary prosthesis, used to augment or otherwise change the size or shape of the female breast.
A conventional saline-filled breast implant includes an outer shell of several layers of silicone elastomer having a valve or fill port. The prosthesis is typically implanted into the breast cavity in an empty or only partially filled state. The implant is then inflated to its final size by means of the valve or fill port. This helps reduce the size of the needed incision, and enables a surgeon to adjust and even microadjust the volume of the implant. Unfortunately, the valve or fill port is sometimes noticeable to the touch.
Many or even most implants are manufactured to a given size and shape, and are implanted without means or expectation of changing their size after implantation or initial filling when first inserted into the breast. However, in many situations it is desirable to be able to adjust the size of the implant over a substantial period of time. If the volume can later be adjusted, an implant of lesser initial volume can be implanted, and as the post-surgical swelling goes down, the implant used as a prosthesis can be enlarged. Also, because often the procedure is for cosmetic purposes, it is useful to be able to make a later adjustment of size without having to replace the prosthesis with one of a different size, which would require a subsequent surgical procedure.
One problem with many conventional adjustable implants is that they require a valve to be part of the implant.
It would be advantageous to provide an adjustable volume implant which does not require a valve or other access port for receiving fluid for adjustment.
Prior to implantation of a more permanent prosthesis, it is common practice to utilize a more temporary implant, for example, what is known as a “tissue expander” in order to gradually create the space necessary for the more permanent prosthesis. Keeping living tissues under tension by means of a tissue expander causes new cells to form and the amount of tissue to increase. Conventionally, a tissue expander comprises an inflatable body, having an inflation valve connected thereto. The valve may be formed into the inflatable body itself or may be remotely located and connected to the inflatable body by means of an elongated conduit.
The inflatable body of the tissue expander is placed subcutaneously in the patient, at the location of where tissue is to be expanded. The inflation valve, whether on the implant or remote thereto, is also subcutaneously positioned or implanted, and is configured to allow gradual introduction of fluid, typically saline, into the inflation body, by injection with a syringe. After gradual inflation at pre-determined intervals, the skin and subcutaneous tissues overlying the expander are consequently caused to expand in response to the pressure exerted upon such tissues by the inflatable body as solution is gradually introduced therein.
After gradual inflation at pre-determined intervals, which may extend over weeks or months, the skin and subcutaneous tissue will expand to the point where further medical procedures can be performed, such as the permanent implantation of a prosthesis, plastic and reconstructive surgery, or for use of the skin and subcutaneous tissue for use in some other part of the body.
During a mastectomy, a surgeon often removes skin as well as breast tissue, leaving the remaining chest tissues flat and tight. To create a breast-shaped space for a reconstructive implant, a tissue expander is sometimes used as described above.
In any event, it should be appreciated that locating the fill valve on a prosthesis such as a tissue expander or adjustable implant requires considerable practitioner skill. Attempts to make products which facilitate this include the development of various products having structure, for example, embedded magnets or a raised ring, for assisting physicians in locating the valve.
It has also proven difficult to develop a flexible protective material that is effective as a puncture resistant material while also being safe for implantation in the body. A puncture resistant material used as a component of a breast implant or tissue expander would ideally be sufficiently flexible such that the implant could still be folded or rolled and inserted through a small incision while also providing resistance to needle punctures aimed at inflating the implant/expander to its final size.
Bark et al., U.S. Pat. No. 5,066,303 discloses a self-sealing tissue expander with a shell having a flowable sealing material. According to Bark et al., fluid infusion into the shell can be done directly through the shell, without the need for a fluid entry port.
Schuessler, U.S. patent application Ser. No. 12/543,795, filed on Aug. 19, 2009, the entire disclosure of which is incorporated herein by this specific reference, discloses a fluid filled implant including a self-sealing shell.
There is a need for improved temporary tissue expanders, more permanent adjustable implants, and other inflatable prostheses. The present invention addressed this need.